Wedge con­nec­tions (see pic­tu­re) are used to­day for the se­cu­re at­tach­ment of shafts and hubs of pre­do­mi­nant­ly hea­vy disks, wheels and cou­plings in high-ton­na­ge ma­chi­nes such as ex­cava­tors and agri­cul­tu­ral equip­ment. In other words, wedge con­nec­tions are used when ma­chi­nery is sub­ject to se­ve­re ope­ra­ting con­di­ti­ons and mu­tu­al, im­pact tor­que. The forces are trans­mit­ted in the­se ca­ses by fric­tion lo­cking and if this is not suf­fi­ci­ent, the form-lo­cking con­nec­tion will co­me ad­di­tio­nal­ly in­to play. Wedge con­nec­tions brace the shaft and hub against each other wi­th wed­ges that have an in­cli­ne of 1:100 and la­te­ral cle­arance in the shaft and hub key­way. The wedge con­nec­tion the­r­e­fo­re oc­cu­p­ies a po­si­ti­on bet­ween a trac­tion con­nec­tion and a form-lo­cking connection.

The ad­van­ta­ges of this ty­pe of con­nec­tion are the mo­re uni­form dis­tri­bu­ti­on of forces over the en­ti­re area, the re­du­ced wear and tear as se­ve­ral la­te­ral sur­faces are si­mul­ta­neous­ly load-bea­ring, and the trans­mis­si­on of hig­her and va­ria­ble torques.

Di­s­ad­van­ta­ges: con­sider­a­b­ly mo­re ex­pen­si­ve, mo­re mark­ed wea­k­e­ning of shaft and hub, and high notch effect.

The­re are dif­fe­rent ty­pes of wedge, which dif­fer in shape and pro­fi­le (see pic­tu­re be­low). The dif­fe­rent ty­pes of wedge are set by DIN 6881 (sadd­le keys), DIN6883 (flat keys), DIN 6886, DIN 6884 (flat gib keys), DIN 6889 (gib-head sadd­le keys).

Flat keys (DIN 6883 and 6884) have on­ly very low form-lo­cking but are cha­rac­te­ri­sed by a si­gni­fi­cant­ly lower notch ef­fect than slot wedges.

Sadd­le keys (DIN 6881 and 6889) are roun­ded on the lower sur­face so that they fit di­rect­ly on the shaft dia­me­ter (trans­mis­si­on of force the­r­e­fo­re by fric­tion locking).

Tan­gen­ti­al keys (DIN 268 and 271) are sui­ta­ble for high and va­ria­ble tor­ques. They are al­so used for split hubs (e.g. for fly­wheels). In this ca­se, a pair of wed­ges are pla­ced 120 de­grees against each other tan­gen­ti­al­ly on the shaft circumference..

Wedge con­nec­tions (see pic­tu­re) are used to­day for the se­cu­re at­tach­ment of shafts and hubs of pre­do­mi­nant­ly hea­vy disks, wheels and cou­plings in high-ton­na­ge ma­chi­nes such as ex­cava­tors and agri­cul­tu­ral equip­ment. In other words, wedge con­nec­tions are used when ma­chi­nery is sub­ject to se­ve­re ope­ra­ting con­di­ti­ons and mu­tu­al, im­pact tor­que. The forces are trans­mit­ted in the­se ca­ses by fric­tion lo­cking and if this is not suf­fi­ci­ent, the form-lo­cking con­nec­tion will co­me ad­di­tio­nal­ly in­to play. Wedge con­nec­tions brace the shaft and hub against each other wi­th wed­ges that have an in­cli­ne of 1:100 and la­te­ral cle­arance in the shaft and hub key­way. The wedge con­nec­tion the­r­e­fo­re oc­cu­p­ies a po­si­ti­on bet­ween a trac­tion con­nec­tion and a form-lo­cking connection.

The ad­van­ta­ges of this ty­pe of con­nec­tion are the mo­re uni­form dis­tri­bu­ti­on of forces over the en­ti­re area, the re­du­ced wear and tear as se­ve­ral la­te­ral sur­faces are si­mul­ta­neous­ly load-bea­ring, and the trans­mis­si­on of hig­her and va­ria­ble torques.

Di­s­ad­van­ta­ges: con­sider­a­b­ly mo­re ex­pen­si­ve, mo­re mark­ed wea­k­e­ning of shaft and hub, and high notch effect.

The­re are dif­fe­rent ty­pes of wedge, which dif­fer in shape and pro­fi­le (see pic­tu­re be­low). The dif­fe­rent ty­pes of wedge are set by DIN 6881 (sadd­le keys), DIN6883 (flat keys), DIN 6886, DIN 6884 (flat gib keys), DIN 6889 (gib-head sadd­le keys).

Flat keys (DIN 6883 and 6884) have on­ly very low form-lo­cking but are cha­rac­te­ri­sed by a si­gni­fi­cant­ly lower notch ef­fect than slot wedges.

Sadd­le keys (DIN 6881 and 6889) are roun­ded on the lower sur­face so that they fit di­rect­ly on the shaft dia­me­ter (trans­mis­si­on of force the­r­e­fo­re by fric­tion locking).

Tan­gen­ti­al keys (DIN 268 and 271) are sui­ta­ble for high and va­ria­ble tor­ques. They are al­so used for split hubs (e.g. for fly­wheels). In this ca­se, a pair of wed­ges are pla­ced 120 de­grees against each other tan­gen­ti­al­ly on the shaft circumference..